Virus infection of the upper air way is perhaps the most common infection in human. A variety of agents are associated with acute viral respiratory tract infections (VRTI) including picornavirus (rhinovirus, most commonly), coronavirus, respiratory syncytial virus (RSV), influenza A and B, parainfluenza viruses, and adenovirus. The clinical syndromes of acute VRTI range from mild illnesses such as the common cold to severe, potentially life-threatening conditions such as severe influenza A infection.
The importance of VRTI is immense. There are considerable costs associated with VRTI in terms of decreased productivity and time lost from work or school, visits to healthcare providers, and amount of drugs prescribed. Recent data suggest that the total annual cost of VRTIs in the United States is $25 billion [Fendrick A M, et al., Value in Health 2001; 4:412]. Approximately 500 million episodes of VRTI occur each year in the US accounting for 84 million visits to clinicians [ibid.]. Another important factor contributing to the impact of VRTIs is the inappropriate use of antibiotics. This significantly adds to the cost of management and to the increasing prevalence of antibiotic-resistant bacteria.
Moreover, the possible effects of the next influenza pandemic has been estimated in the United States to result in 89,000 to 207,000 deaths, 314,000 to 734,000 hospitalizations, 18 to 42 million outpatient visits, and 20 to 47 million additional illnesses (Fendrick A M, 2001). Patients at high risk (15% of the population) would account for approximately 84% of all deaths. The estimated economic impact is US$71.3 to $166.5 billion, excluding disruptions to commerce and society (Meltzer M I, et al., Emerging Infectious Diseases 5: 659-671; 1999).
At present, vaccination is applied to prevent such pandemics and make cost savings. An intake of 60% is needed to be economically viable. That is not easily achieved and may not be possible within the time required for vaccine effectiveness, especially if two doses of vaccine are required.
Thus, there is a need for a treatment that is effective when viral disease strikes, that is easily administered, is rapidly acting and terminates the illness in a short time.